Conventionally, there has been known an energy storage apparatus which includes a plurality of battery cells, and a plurality of energy storage cell holders each of which is disposed between the battery cells disposed adjacently to each other (see JP-A-2014-35969).
To be more specific, as shown in FIG. 21 and FIG. 22, the energy storage apparatus includes a plurality of battery cells 501 arranged in a row in a predetermined direction (stacking direction), and a plurality of energy storage cell holders 502 each of which is disposed between the battery cells 501 disposed adjacently to each other. The energy storage cell holder 502 includes a corrugated plate portion 503 which is disposed between the battery cells 501 and expands in a direction orthogonal to the stacking direction, and engaging portions 504 which project from four corners of the plate portion 503 in the stacking direction. The energy storage cell holders 502 disposed adjacent to each other are positioned relative to each other as the engaging portions 504 of these energy storage cell holders 502 mutually engage with each other. The battery cell 501 is positioned relative to the energy storage cell holder 502 by making the engaging portions 504 engage with four corners of the battery cell 501. In such a configuration, between the corrugated plate portion 503 and the battery cell 501 disposed adjacently to the plate portion 503, a plurality of cooling medium passages 505 extending in a width direction of the battery cell 501 are formed. A sealing projection 506 extending in a width direction is formed on an upper edge and a lower edge of the plate portion 503 of the energy storage cell holder 502 respectively. By bringing the sealing projections 506 into pressure contact with an insulation seat formed on a surface of the battery cell 501 such that the sealing projections 506 bite into the insulation seat, sealing is applied such that a cooling medium made of cold air does not leak from an upper portion and a lower portion of the cooling medium passage 505.
As shown in FIG. 22, in the energy storage apparatus 500, in the pair of energy storage cell holders 502 disposed adjacently to each other with the battery cell 501 interposed therebetween, a height position of the sealing projection 506 formed on a surface of the plate portion 503 of one energy storage cell holder 502 which is directed to the battery cell 501 (a surface of the energy storage cell holder 502 disposed on a left side which is directed to a right side in FIG. 22) and a height position of the sealing projection 506 formed on a surface of the plate portion 503 (a surface of the energy storage cell holder 502 disposed on a right side which is directed to a left side in FIG. 22) differ from each other. In each energy storage cell holder 502, in a portion of each engaging portion 504 which faces the battery cell 501, the sealing projection 506 extends in a straight line in the stacking direction from the plate portion 503 to a distal end of the engaging portion 504. Accordingly, a height position of the sealing projection 506 formed on the engaging portion 504 extending toward one side in a stacking direction (a right side of the energy storage cell holder 502 disposed on a left side of the battery cell 501 disposed at the center in FIG. 22), and a height position of the sealing projection 506 formed on the engaging portion 504 extending toward the other side (a left side of the energy storage cell holder 502 disposed on a right side of the battery cell 501 disposed at the center in FIG. 22) differ from each other. In such a configuration, with respect to the engaging portions 504 which correspond to each other of the energy storage cell holders 502 disposed on both sides of the battery cell 501 in the stacking direction, although distal ends of the engaging portions 504 are made to opposedly face each other, the height positions of the sealing projections 506 are made different from each other between the pair of engaging portions 504 whose distal ends are made to opposedly face each other. Accordingly, in the above-mentioned pair of engaging portions 504, a gap between a distal end of the sealing projection 506 formed on the engaging portion 504 extending toward one side and a distal end of the sealing projection 506 formed on the engaging portion 504 extending toward the other side becomes large (to be more specific, becomes larger than a gap between the distal ends of the engaging portions 504). As a result, a cooling fluid leaks from the above-mentioned gap (formed between the battery cell 501 and the engaging portions 504 extending in the stacking direction at four corners of the battery cell 501). In this case, cooling efficiency or the like of the battery cell 501 is lowered.